<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>

    </style>
</head>

<body>
    <ul>
        <li>123</li>
        <a
            href="https://www.bilibili.com/video/BV1Sy4y1C7ha/?p=233&spm_id_from=pageDriver&vd_source=480c28921b1b6c12cb33e4a6f0a94947">视频链接</a>
    </ul>
    <script>
        // 1.创建节点元素节点
        let li = document.createElement('li');
        //  2.添加节点
        let ul = document.querySelector('ul');
        ul.appendChild(li);
        //  3. 在指定初添加节点
        let lili = document.createElement('li');
        ul.insertBefore(lili, ul.children[0]);
    </script>
</body>

</html>